Expository Text of the Dolphins

Expository Text of the Dolphins

A look at the smartest marine mammals: dolphins

Of all the aquatic mammalsdolphins are probably the most sympathetic in almost all cultures and geographies on the globe. Their presence in the marine waters is always celebrated and welcomed, and their playful movements interpreted as a clear sign of intelligence, as these smiling-looking, plump-bodied animals possess brains much more similar to those of primates than originally believed.

Dolphins are, like the rest of the cetaceans, the result of the evolutionary adaptation of terrestrial mammals (probably artiodactyls, related to modern hippos) that returned to marine life around 50 million years ago. However, when we speak of dolphins, we generally refer to oceanic dolphins, that is, those that live in the seas (or in ponds, in captivity) and not to their river and freshwater cousins ​​(the superfamily of the platanistoids), with which they have important differences.

This means that dolphins are not related to fish, and in fact the latter make up a large part of their diet, strictly carnivorous. On the contrary, in the tree of life, dolphins are close to whales and killer whales, and constitute a family of their own (

Delphinidae) of about 37 species known. Broadly speaking, these animals have fusiform bodies, between 2 and 8 meters long, with a elongated snout and a blowhole at the top of the head, which serves as an opening for to breathe. Dolphins do not have gills but lungs, but they are able to withstand the breathing up to 10 minutes under water.

Regarding your habitatDolphins are found in practically all the seas of all the oceans of the planet, although they tend to prefer the warm waters of the tropics. They are skilled swimmers and hunters, capable of swimming at speeds close to 50 kilometers per hour. And they also have the ability to emit a wide range of sounds, which they not only use to communicate with each other but also as radar, through echolocation. A sound wave is emitted that bounces off the environment and when it returns to the dolphin's ears, it brings with it recognizable information. This is a very precise and unique location system for dolphins among marine animals.

The most intelligent marine mammals

What most attracts the attention of dolphins is their degree of intelligence, comparable to that of a chimpanzee (or even a 3-year-old child). It is known that these animals have a high degree of sociability, so they are capable of hunting in a herd, coordinating through sounds similar to clicking, hissing, and bursts of other sounds, similar to those used for echolocation.

Groups of dolphins can reach up to 1000 individuals, linked to each other through strong social ties, as evidenced by the fact that help their injured fellows rise to the surface to breathe, or have unique whistles assigned to each other to identify themselves amidst the herd. This does not mean that there are no competitive dynamics, especially among males, and it is common among adults to exhibit scars from fighting for access to females or to the food.

Dolphins, however, along with humans and a few other primate species, are the only known animals capable of using tools to solve problems. They have been seen in the Indian Ocean covering their snouts with sea sponges to protect them from rubbing against stones when foraging for food, a technique that mothers teach their young.

Similarly, dolphins can form alliances with humans, either to face predators (like certain species of sharks), or in exchange for rewards, by way of training. In fact, trained dolphins are used as part of the maritime military forces of some countries, and in numerous water shows where they play with balls or dance for the public. There have even been cases of cooperative fishing between humans and dolphins, spontaneously teaming up so that both species benefit.

Despite this, many human activities are harmful to dolphins, and a significant number of they die each year from injuries caused by ship propellers, or trapped and suffocated in nets to fishing. To this must be added that dolphins are part of certain Asian diets, such as in Taiji (Japan) or the Faroe Islands, and how sensitive these animals are to the levels of sea ​​pollution with pesticides, metals heavy duty and other agricultural and industrial wastes. Dolphins have no natural predators. Damage to your communities and ecosystems they are, for the most part, the consequence of human actions.

References:

• "Expository text" in Wikipedia.
• "Delphinidae" in Wikipedia.
• "Dolphins" in National Geographic.
• "Curiosities about dolphins" in Very interesting.
• "Top 10 facts about Dolphins" in World Wildlife Fund (WWF).
• "Dolphin (mammal)" in The Encyclopaedia Britannica.

What is an expository text?

A expositive text It is a type of writing whose mission is to provide the reader, in an objective way, specific and specific information on a specific topic. In this it differs from other textual types, such as argumentative text or the narrative text, since the expository text does not contain or arguments or opinions in favor of a perspective, nor any kind of story or narration.

Expository texts focus on information, so they are usually impersonal and rigorous in their approach to the subject. They are texts in which data, observations, textual citations and other resources predominate to expose the reader to an aspect of reality.

To write an expository text we must document ourselves on the desired topic and then reproduce the ideas, from the most general to the most specific (or vice versa), without involving our own points of view on the matter and adhering to the strictly informative.

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